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expanding pack idx fanout table

From
Shawn Pearce <spearce@spearce.org>
Date
Jul 8, 2013, 15:54 UTC
Message-ID
<CAJo=hJsto1ik=GTC8c3+2_jBuUqcAPL0UWp-1uoYYMpgbLB+qg@mail.gmail.com>

Has anyone studied the impact of converting the pack idx fanout table from 256 entries to 65536 entries?

Back of the envelope estimates for 3.1M objects in linux.git suggests a 2^16 fanout table would decrease the number of binary search iterations from ~14 to ~6. The increased table costs an extra 255 KiB of disk. On a 70M idx file this is noise.

I'm starting to wonder if increasing the fanout table once the object count is above a certain threshold is a reasonable optimization for larger repositories.

Next: Junio C Hamano
Message 1 of 4 in “expanding pack idx fanout table”
  1. Shawn PearceJul 8, 2013
  2. Junio C HamanoJul 8, 2013
  3. Shawn PearceJul 8, 2013
  4. Jeff KingJul 9, 2013

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